De Waal’s own experiments suggest that capuchin monkeys are sensitive to fairness. If another monkey gets a tasty grape, they will not cooperate with an experimenter who offers a piece of cucumber (Nature, vol 425, p 297). A similar aversion has been spotted in dogs (New Scientist, 13 December 2008, p 12), and even rabbits seem affected by inequality, leading de Waal to believe that an ability to detect and react to injustice is common to all social animals. “Getting taken advantage of by others is a major concern in any cooperative system,” he says.

This article mostly just regurtitates some tired and fragile “evolutionary” explanations for fairness and revenge, but there are a few interesting tidbits, like some experiments with monkeys and this joke:

A genie appears to a man and says: “You can have anything you want. The only catch is that I’ll give your neighbour double.” The man says: “Take out one of my eyes.”